Think back to when you introduced your first companion pet to your home and the food and water bowls you purchased. Did you go with bowls that had cute paw prints painted on them? Did you choose bowls that were shaped like bones? Did you purchase stainless steel to match your appliances? Did you buy the least expensive bowls?
The answer about the best type of bowl material for your companion pet is not so clear cut.
A study from the United Kingdom examined three different bowl materials: plastic, ceramic and stainless steel. The researchers examined whether bacterial adhesion was more common with a particular material that the others as well as bacterial diversity.
On day 7, the stainless steel bowls had the highest bacterial count, but the measurements taken on day 14 demonstrated that plastic had the highest remaining count. Overall, the researchers found the ceramic bowl had the lowest bacterial count over the 14-day period.
High bacterial count is not the same as bacterial diversity. Bacterial diversity refers to the number of bacteria species present. Interestingly, in this regard, the ceramic bowls had the highest amount of species identified.
Also, if plastic, stoneware or ceramic bowls are scratched, chipped or cracked, the crevices can harbor bacteria.
Bisphenol A has been implicated as an endocrine disrupting chemical found in plastic or metals like aluminum that is lined with it to prevent an aluminum taste or corroding. Stainless steel items do not have this lining. In dogs, BPA has been shown to alter the gut microbiome and cause metabolic changes.
However, some studies are showing that the alternatives to BPA may not, in fact, be any safer.
Phthalates are chemicals used to make plastics more flexible or resilient. Their impact on health is largely unknown. In particular, one phthalate, Di (2-ethylhexyl) phthalate (DEHP), is an endocrine disruptor and could cause cancer.
A study by Kim Wooten and Philip Smith at Texas Tech University demonstrated that plastic bumpers on bowls leached both DEHP and BHA when immersed in synthetic saliva. Additionally, they simulated chewing of those bumpers during the immersion, which increased the concentrations of both chemicals compared to unchewed and newer bumpers.
In 2017, The United States Consumer Product Safety Commission (CPSC) issued a final rule that prohibits more than 0.1 percent concentrations of at least eight phthalates in children’s toys and child care articles.
The United States Government regulations are lacking with regard to the importation of certain goods containing lead. Glazes found on ceramics, porcelain, stoneware or earthenware may contain elevated and unacceptable levels of lead. This is of potential concern with goods made in Mexico or China.
According to the Food and Drug Administration’s (FDA) website (November 2010):
“If the ceramicware contains lead and is properly made, it can be sold in the U.S. The FDA recently published guidance that addresses the safety and labeling concerns for traditional pottery and ornamental ceramicware that may contain lead that can contaminate food. The guidance is entitled ‘(1) The Safety of Imported Traditional Pottery Intended for Use with Food and the Use of the Term “Lead Free” in the Labeling of Pottery; and (2) Proper Identification of Ornamental and Decorative Ceramicware.’”
The FDA recently issued an Import Alert on October 22, 2018:
“FDA has identified dietary lead exposure as a significant public health issue. Lead and cadmium are components of the glaze used in making ceramicware, and can leach into foods in significant amounts when the glaze is improperly formulated, applied, or fired. Lead can also leach from the colors used to make patterns in some ceramicware. In FY’93, approximately 15% of the imported lots analyzed were found violative for lead and/or cadmium. Districts may detain, without physical examination, ceramicware for food use from the manufacturers and/or shippers identified in the Red List to this alert.”
At this point in time, silicone is considered safe. Several blog sites like Mind Body Green discuss studies that have been conducted. The authors admit that they continue to sell silicone products because they are better than plastic and pose less of a health risk. They do say that the silicone should be high quality, ideally “medical grade” but at least “food grade.”
Which type of bowl to choose? It really depends on your lifestyle, but we aim for stainless steel.
No matter what material you choose, you should follow some guidelines:
- Scratched or cracked plastic bowls should be recycled.
- Do not use cracked or chipped ceramics, earthenware or stoneware.
- Look for “BPA and Phthalate Free” for plastic bowls. However, this is a leap of faith since that marketing claim is not regulated.
- If you choose ceramic, earthenware or stoneware, make sure it is made in a country that has lead laws similar to the United States. Remember, the bowls can still contain lead.
- Choose “BPA and Phthalate Free” products even though the alternatives may not be the best
- Wash, wash, wash the bowls daily!
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Wright, Coralie, and Aisling Carroll. “Microbiological Assessment of Canine Drinking Water: the Impact of Construction Material on the Quantity and Species of Bacteria Present in Water Bowls.” Hartpury Student Research Journal, 29 Aug. 2018, studentjournal.hartpury.ac.uk/2018/08/29/microbiological-assessment-of-canine-drinking-water-the-impact-of-construction-material-on-the-quantity-and-species-of-bacteria-present-in-water-bowls/.